Safety device and mechanism comprising one such device used to manoeuvre a closing or sun protection installation

ABSTRACT

A safety mechanism for a closing installation, comprising a shaft and an element having teeth for cooperating with a catch which oscillates during rotational movements of the shaft. The mechanism further comprises a safety system including a ring for braking the oscillatory movement of the catch. The movement of the ring is controlled by a detecting system that detects the state of a spring which used to compensate the torque exerted on the shaft by the screen body.

The invention relates to a safety device for a closing or sun-protectioninstallation. The invention also relates to a mechanism for manoeuvringsuch an installation.

Closing installation is understood to mean doors, portals, shutters andequivalent equipment.

In a closing or sun-protection installation, it is known to use awinding mechanism for manoeuvring a screen body, a door, a shutter orequivalent. Such a mechanism may be actuated mechanically, thanks to astrap or a crank, or electrically, thanks to a motor which is most oftenof brake motor type. It is known to compensate the torque exerted on thewinding mechanism by the weight of the screen body by means of one ormore so-called compensating springs.

Furthermore, it is known to provide safety devices, sometimes called“anti-fall”, to prevent the screen body from falling in the event ofmechanical rupture in the kinematic chain controlling the screen body.

FR-A-2 242 010 describes a catch or rocking lever which comprises an armcapable of coming into engagement with an outer toothing of a wheel fastwith a shaft for winding a screen body. This rocking lever comprises asecond arm provided with a roller which forms counterweight for thefirst, while the roller rolls on undulations formed on the periphery ofa second wheel, fast with the first. Gravity tends to apply the rolleron the periphery of the second wheel, with the result that the first armof the rocking lever oscillates between a position of engagement and ofdisengagement with respect to the teeth of the first wheel without,however, abutting thereagainst, this being effectively the case when thespeed of rotation of the wheels is reduced. However, if the speed ofthese wheels increases, particularly in the case of the screen bodyfalling, the roller no longer follows the peripheral undulations of thesecond wheel exactly, by reason of the inertia of the rocking lever andtends to remain detached from the second wheel, the first arm in thatcase being in position of engagement with the teeth of the first wheeland provoking a sudden blocking of the drive system.

Documents CH-A-573 146, DE-A-26 17 784 and DE-A-40 02 074 describedevices in which the peripheral toothing of a single wheel performs botha function of blockage and a function of undulation of a catch or of arocking lever.

DE-A-29 15 547 provides replacing the teeth by rods which ensure boththe undulation and the blocking of a catch. This device is active forbraking the rotation of a winding shaft only beyond a certain speed ofthis shaft.

In the devices of the state of the art, a shock is produced, duringblocking of the winding shaft, which is detrimental to the safety deviceitself and to the drive mechanism which it is supposed to protect. Thisinvolves dimensioning the parts constituting these safety devicesaccordingly, by using relative noble materials, or providing dampingsystems such as those envisaged in EP-A-0 671 543. This increases thecost price of this type of device and may increase their dimensions. Inaddition, in the so-called compensated installations, i.e. comprisingcompensating springs, a fall at reduced speed is possible, the devicesof the prior art being in that case globally inefficient.

In effect, in this type of installations, it is possible to disengagethe link between the drive motor and the shaft, such a disengagementmaking it possible to manoeuvre the screen body manually, for example inthe absence of current supplying an electric motor. In the case of sucha disengagement, there no longer exists a kinematic link between themotor and the screen body and only a correct equilibrium of thecompensation prevents the screen body from falling. It is usual toadjust the compensation in dominant manner with respect to the weight ofthe screen bpdy in order to overcome the possible deficits ofcompensation which might occur in the life duration of the installation,particularly by reason of the running-in and inevitable wear of theparts. However, this is not sufficient to overcome the failure or anabnormal fatigue of a compensating spring, in which case thedisequilibrium may be sufficiently great to create, at the instant ofdisengagement, a slow but dangerous fall of the screen body. Such asituation may occur in particular in the case of an installationcomprising a plurality of compensating means, such as spring boxes,particularly in the case of rupture of one of the springs. Such asituation may also occur in the case of an installation comprising onesole compensating spring whose stiffness constant decreases withfatigue.

Such failures present an insidious nature, which renders themparticularly dangerous. In effect, they do not appear when theinstallation is functioning normally, i.e. when the installation ismanoeuvred by the motor, which is generally the case. As it isconventional to overdimension the motor and the structure in order to beable to absorb the hard spots and the variations of coefficient offriction which inevitably appear in the life of the installation, aninsufficient equilibrium resulting from this type of failure is likewiseconcealed. It is only at the moment of disengagement, when a manualmanoeuvring is needed, which occurs at an often unexpected instant, thatthe phenomenon appears.

Furthermore, it is known from U.S. Pat. No. 2,878,865 to couple acompensating spring to a catch which does not oscillate during themovements of lowering of a door. This non-oscillating catch blocks thedescent of the screen body under the effect of a deficit between thetorque produced by the compensating spring and that due to the weight ofthe door. Descent of a door equipped with such a mechanism is thus notmanoeuvrable by a direct action on said door, which is in practiceredhibitory as a door or a metal shutter of a shop must be able to beclosed, including in the event of a power cut. In effect, a directaction to descend the door is detected by the mechanism as a deficit ofcompensation. In addition, as the blocking of the catch is obtained by adeficit of compensation, it is necessary that the compensating springsbe overdimensioned in order that the efforts that they deploy always begreater than the effect of the weight of the lowering door, otherwisethe movement of lowering of the screen body or of the shutter by theaction of the motor induces successive blockages/unblockages of thecatch which may, in the long run, damage the mechanism.

It is a more particular object of the invention to overcome thesedrawbacks by proposing a safety device for a closing or sun protectioninstallation comprising an oscillating catch which functions correctly,including in the event of failure of a compensating means such as aspring.

In this spirit, the invention relates to a safety device for a closingor sun-protection installation comprising a mechanism for driving ameans for closing an opening, this mechanism including a fast shaft andan element provided with a toothing adapted to cooperate with at leastone catch which oscillates during rotational movement of said shaft andadapted to immobilize it in rotation. This device is characterized inthat it comprises braking means or means for blocking the catch in itsoscillatory movement, said braking or blocking means being controlled bymeans for detecting the state of a means for compensating the torqueexerted on this shaft by the closing means.

Thanks to the invention, a failure of a compensating means such as aspring, and more particularly a rupture of such a spring, induces abraking of the oscillating catch, this making it possible to maintain itin position of blocking of the element provided with a toothing. Thisleads to an immediate immobilization of the shaft, without it beingnecessary for the shaft to have a predetermined speed of rotation. Inother words, the braking means and the associated detection means makeit possible to react immediately to a failure of the compensating means,before a substantial variation in speed of the rotating shaft,corresponding to a potentially dangerous displacement of the closuremeans, occurs. The device of the invention functions, in practice,thanks to a detection of the torque due to the compensating spring andnot by the detection of a deficit of compensation. For the installationsof compensated type, the device ensures dual protection, namely aprotection at low speed, which is the case when the failure concerns thecompensating means, and at high speed, which is the case for the otherfailures. In practice, it so happens that, in the compensatedinstallations, the fall of the closing means, i.e. most often of thescreen body, is most often the fact of a failure of the compensatingmeans. Thanks to the invention, the life duration of the installation ismaintained since, in the most frequent case, no shock is created whenthe safety device is activated. The device of the invention is alsosimpler, lighter, less expensive and less cumbersome than those of thestate of the art.

According to advantageous aspects of the invention, this deviceincorporates one or more of the following characteristics:

-   -   The braking or blocking means comprise a shoe mobile axially        with respect to the afore-mentioned shaft and adapted to come        into abutment against the catch. This shoe advantageously bears        at least one element in relief adapted to cooperate with a        corresponding element in relief provided on a member fast in        rotation with the compensating means, for controlling the axial        position of the shoe with respect to the catch.    -   The elements in relief provided respectively on the        afore-mentioned member and shoe may comprise ribs and grooves        adapted to engage in one another. Such ribs and grooves make it        possible, for example by a movement of screwing/unscrewing, to        control the axial position of the shoe. In addition, at least        certain of the afore-mentioned elements in relief may be        provided to be formed on tongues extending through openings made        in the element fast with the shaft.    -   The afore-mentioned shoe and member are advantageously disposed        axially on either side of the element fast with the shaft, being        kinematically connected by the cooperation of the aforementioned        elements in relief. Means for applying an elastic effort of        displacement of the shoe towards the catch may be provided. In        that case, the member and the element fast with the shaft are        advantageously provided with ribs between which at least one        compression spring is disposed, exerting a rotational torque of        the member fast with the compensating means with respect to the        element fast with the shaft.    -   The shoe is a ring disposed inside the shaft and around an        element forming support and/or motorization assembly for the        mechanism.    -   The braking or blocking means are adapted to displace or tip the        catch towards a braked or blocked position. In that case, there        may be provided a friction pellet, mounted on the catch or        thereopposite, and intended to receive the catch in abutment or        to come into contact with a bearing surface. Furthermore, the        braking or blocking means may comprise a surface formed on a        part fast in rotation with the compensating means and intended        to exert, directly or indirectly, an effort of displacement or        of tipping on the catch. This surface may extend in a direction        substantially inclined with respect to an axis of rotation of        the shaft, this surface in that case forming a ramp adapted to        displace the catch towards its braked or blocked position. This        surface may also be substantially radial with respect to an axis        of rotation of the shaft and be adapted to cooperate with a        finger of the catch in order to tip it about its oscillation        axis, towards a braked or blocked position by engagement with        the toothing. Means for returning the catch opposite the braked        or blocked position may be provided. The braking or blocking        means may also comprise at least one shuttle adapted to displace        the catch in the direction of a fixed blocking toothing. In that        case, this shuttle is advantageously provided with an elastic        means for adjusting its length, taken between a bearing surface        and the catch. In addition, means may be provided for elastic        return of the braking or blocking means towards a position in        which they exert on the catch an effort of displacement or of        tipping towards the braked or blocked position.    -   The catch may be mounted on a fixed element of the installation        or, on the contrary, on an element fast in rotation with the        shaft, being intended to be driven in rotation thereby.    -   The braking or blocking means, the detection means and the        compensating means are arranged around an element forming        support and/or motorization assembly for the mechanism.

According to a first form of embodiment of the invention, thecompensating means is a spring tightened around an end support of theshaft, between a part fixed with respect to the support and an annularmember adapted to rotate thereabout by being driven by the shaft, thecatch being mounted to pivot about a pin fixed with respect to thesupport.

According to a second embodiment of the invention, the compensatingmeans is a spring tightened by a weight and fast with an annular membersurrounding an end support of the shaft, the catch being mounted topivot about a pin fixed with respect to this support.

According to a third embodiment of the invention, the compensating meansis a spring tightened around a motorization assembly disposed inside theshaft, the catch being mounted to pivot about a pin fixed with respectto a part forming end support of this shaft.

According to a fourth embodiment of the invention, the compensatingmeans is a spring integrated in a spring box disposed inside the shaft,between the latter and a fixed shaft, the spring box also comprising thecatch, the braking means and the detection means.

The invention also relates to a mechanism for manoeuvring a closing orsun protection installation which comprises a safety device as describedhereinabove. Such a mechanism is more reliable, more compact and lessexpensive than those of the state of the art. In particular, it issecured against a failure of a compensating spring.

The invention will be more readily understood and other advantagesthereof will appear more clearly in the light of the followingdescription of seven forms of embodiment of a maneouvring mechanismequipped with a safety device in accordance with its principle, givensolely by way of example and made with reference to the accompanyingdrawings, in which:

FIG. 1 is a view in perspective of certain elements constituting amechanism according to the invention.

FIG. 2 is a view in perspective of the elements of FIG. 1, seen fromanother angle.

FIG. 3 is a partial section of a mechanism according to the inventionincorporating the elements shown in FIGS. 1 and 2.

FIG. 4 is a view similar to FIG. 3 for a mechanism in accordance with asecond form of embodiment of the invention.

FIG. 5 is a view similar to FIG. 3 for a mechanism in accordance with athird embodiment of the invention.

FIG. 6 is a view similar to FIG. 3 for a mechanism in accordance with afourth embodiment of the invention.

FIG. 7 is a partial section through a mechanism in accordance with afifth embodiment of the invention.

FIG. 8 is a section along line VIII-VIII in FIG. 7.

FIG. 9 is a section along line IX-IX in FIG. 8.

FIG. 10 is a section along line X-X in FIG. 7.

FIG. 11 is a section similar to FIG. 7 for a mechanism in accordancewith a sixth embodiment of the invention.

FIG. 12 is a section along line XII-XII in FIG. 11.

FIG. 13 is a section along line XIII-XIII in FIG. 11.

FIG. 14 is a section similar to FIG. 7 for a mechanism in accordancewith a seventh embodiment of the invention.

FIG. 15 is a section along line XV-XV in FIG. 14, and

FIG. 16 is a section along line XVI-XVI in FIG. 14.

The mechanism 1 shown partially in FIGS. 1 to 3 is provided for thecontrolled winding, about a substantially horizontal axis X-X′, of ascreen body T allowing an opening O provided in a building to beselectively closed. This mechanism is intended to be supported withrespect to the masonry of a building, by means of a bracket 2 possiblyintegrated in a tunnel box.

The mechanism 1 comprises a tubular shaft 3 of circular section andwhose longitudinal axis merges with axis X-X′. The shaft 3 might presenta polygonal cross-section or another profile.

A support 4, fixed by any appropriate means on the bracket 2, isdisposed inside the tube 3 and is equipped with an annular ring 5 whichsurrounds the support 4 being immobilized thereon in rotation and intranslation. The ring 5 is therefore fixed with respect to the masonryof the building.

A catch 6 is mounted on a mechanical pin 7 passing through an opening 51in the ring 5. A-A′ denotes the geometrical axis of symmetry of theshaft 7. Axes X-X′ and A-A′ are substantially parallel.

The catch 6 comprises a first branch 61 extending radially with respectto the axis A-A′ when the catch 6 is mounted on the pin 7 and a secondbranch 62.

A ring 8 is also mounted about the support 4 and axially immobilizedwith respect thereto thanks to a snap ring 81 engaged in a groove 41 ofthe support 4. The ring 8 is fast in rotation with the shaft 3.

The ring 8 comprises an inner sleeve 82 defining a cylindrical surface83 with circular base of radius substantially equal to the outer radialsurface 43 of the support 4, with the result that the ring 8 may rotateabout axis X-X′ by sliding over the surface 43.

The ring 8 also comprises an outer sleeve 84 provided with bores 85 forpassage of screws (not shown) making it possible to connect the ring 8and the shaft 3 in rotation and in translation.

An annular web 86 joins the sleeves 82 and 84 and is pierced with threeopenings 87.

Three ribs 88, which are radial and substantially planar, are alsoprovided between the sleeves 82 and 84, being perpendicular to the web86.

An inclined toothing 89 is arranged inside the sleeve 84. This toothingis oriented and dimensioned in order to cooperate, if necessary, withthe branch 62 of the catch 6.

An annular member 9 is provided to be mounted about the sleeve 82, beingmaintained axially by a snap ring 91 engaged in a groove 81′ of the ring81. The outer surface 92 of the annular member 9 is substantiallytruncated and stepped. The surface 92 is also provided with a notch 93for receiving and wedging a first end of a compensating spring 10 ofwhich the part nearest this end is wound on the surface 92.

The opposite end of the spring 10 is immobilized on a ring 11 whoseouter shape is likewise truncated, itself immobilized on the support 4thanks to a lug 12.

A motorization assembly (not shown), which may be electrical ormechanical and disposed near the opposite end of the shaft 3, makes itpossible to drive the shaft 3 in rotation about axis X-X′, asrepresented by the double arrow R in FIG. 3.

The annular member 9 is provided with ribs 95 each extending in a radialdirection with respect to a central sleeve 96 and provided with a lug 97for centering a compression spring 30 intended to be housed between arib 95 and a rib 88 which are opposite when the annular member 9 ismounted on the ring 8, as shown in FIG. 3.

As a function of the position of the screen body T with respect to theopening O, the compensating spring 10 is more or less tightened betweenthe annular member 9 and the ring 11. In effect, the shaft 3 drives inrotation the ring 8 which drives, by the cooperation of the ribs 88 and95, the annular member 9. As a function of the direction of rotation ofthe annular member 9 about the axis X-X′, the tension of the spring 10increases or decreases.

During the movements of rotation of the shaft 3 about axis X-X′ forwinding or unwinding the screen body T, the catch 6 oscillates aboutaxis A-A′, this movement of oscillations being generated by thesuccessive contacts between the branch 62 and the teeth of the toothing89 and by the effect of the weight of the branch 61 which is heavierthan the branch 62.

In this embodiment and in the following ones, the catch 6 or equivalentis of non-blocking type by default. It becomes blocking under the effectof the centrifugal force upon a rapid rotation of the shaft 3 orequivalent when the screen body T unwinds.

A ring 20 is interposed between the ring 5 and the face 86 a of the web86 turned towards the ring 5. In fact, the ring 20 is interposed betweenthe face 86 a and the catch 6. The ring 20 has such inner (D_(i)) andouter (D_(c)) diameters that its face 21 turned towards the catch 6 issubstantially aligned with a lateral face 63 of this catch.

In this way, as a function of its axial position, i.e. its positionalong the axis X-X′, the ring 20 is capable of coming into abutmentagainst the catch 6.

The ring 20 is provided with three tongues 22 dimensioned to be engagedin the openings 87 of the ring 8 and each provided, on their face 23turned towards axis X-X′, with a groove 24 in the form of a portion ofhelix.

The annular member 9 is provided with three helicoidal ribs 94dimensioned and arranged so that they may be engaged in the grooves 24of the ring 20.

The angle of inclination of the elements 94 and 24 with respect to axisX-X′ is such that the elements 94 and 24 perform the role of threadsmaking it possible to “screw” the ring 20 on the annular member 9 in thedirection represented by arrow R′ in FIG. 1.

Functioning is as follows:

When the spring 10 performs its role of compensation efficiently, itexerts on the annular member 9 a torque C₁ directed in a direction suchthat it tends to cause the ribs 94 to advance in the grooves 24 in asense of screwing the ring 20 on the annular member 9. Under theseconditions, the ring 20 is drawn towards the web 86, this beingrepresented by the effort F₁ in FIGS. 1 and 3.

In this way, a clearance J is formed between the ring 20 and the lateralface 63 of the catch 6.

In the event of rupture or of failure of the spring 10, the torque C₁ iscancelled or overcome by a torque C₂ exerted in opposite direction bythe springs 30, this having the effect of rotating the annular member 9about axis X-X′ in the direction of arrow R′ in FIG. 1. This induces aneffort of displacement of the ring 20 in the direction of the catch 6,this effort being represented by arrow F₂ in FIGS. 1 and 3.

It will be noted that the torque C₂ has a relatively low value withrespect to the torque C₁. The value of the stiffness constants of thesprings 30 is chosen to that end as a function of that of the spring 10.In this way, braking or blocking of the catch 6 is obtained in the eventof total or virtually total failure of the spring 10 and not in the caseof momentary under-compensation due, for example, to a variation of thediameter of winding of the screen body, as might occur in a devicefunctioning on the basis of a deficit of compensation. These commentsare also applicable, against possible adaptations, to the other forms ofembodiment.

In that case, the ring 20 performs the role of a shoe for braking thecatch 6, as its face 21 comes into contact with the lateral face 63 ofthis catch.

In this way, a failure or a rupture of the spring 10 is detected thanksto elements 8, 9 and 30 and such detection makes it possible to controlthe translation of the ring 20 in the direction of the catch 6 that thering forming shoe can efficiently brake in its movement with respect tothe toothing 89. By being braked, the catch 6 is blocked in engagementin the toothing 89 and thus immobilizes the annular member 8 withrespect to the ring 5, i.e. the shaft 3 with respect to the support 4and to the bracket 2.

In that case, the screen body T no longer risks falling accidentally.

In the second form of embodiment of the invention shown in FIG. 4,elements similar to those of the first bear identical referencesincreased by 100. The mechanism 101 of this embodiment is provided forwinding a screen body T and comprises a shaft 103 mounted on a ring 108,itself supported by a support 104 immobilized with respect to a bracket102 fixed with respect to the masonry of a building.

A ring 105 is mounted at the end of the support 104 and immobilizedaxially thanks to a snap ring 151 and in rotation by cooperation ofshapes.

The ring 105 supports a mechanical pin 107 of which A-A′ denotes thegeometrical axis, while X-X′ denotes the geometrical axis of the tube103 which is also its axis of rotation. Axes A-A′ and X-x′ aresubstantially parallel.

An annular member 109 is arranged on the ring 108 and immobilizedaxially, with possibility of rotation, thanks to a snap ring 181. Theannular member 109 extends axially by a sleeve 192. Around this sleeve192, there is wound a cable 110 from which a weight P is suspended.

As previously, a ring 120 is equipped with tongues 122 provided withgrooves 124 for receiving ribs 194 made on the ring 109, the cooperationof the elements 124 and 194 making it possible to exert on the ring 120efforts F₁ and F₂ of translation parallel to axes A-A′ and X-X′, whichallows the ring 120 to selectively brake a catch 106 mounted on the pin107.

The effort F₁ is generated by the weight P, while the effort F₂ isgenerated by springs 130 interposed between ribs belonging respectivelyto the ring 108 and to the ring 109.

A failure of the means supporting the weight P, particularly a ruptureof the cable 110, has the effect of rotating the ring 109 about axisX-X′. As in the previous embodiment, this induces a displacement of thering 120 in the direction of the catch 106, the ring blocking the catchin engagement in the toothing 189. This results in the ring 108 and thetube 103 being immobilized in rotation with respect to the ring 105 andto the support 104.

Like in the first embodiment, a mechanism for driving the shaft 103 inrotation may be provided at the opposite end of this shaft.

In the third form of embodiment of the invention shown in FIG. 5,elements similar to those of the first embodiment bear identicalreferences increased by 200. The mechanism 201 of this embodiment isprovided for the controlled winding of a screen body T around an axisX-X′ which is also the axis of symmetry of a shaft 203. Around axis X-X′there are disposed a ring 208, an annular member 209, a catch 206, aring 220 and springs 230. A compensating spring 210 is tightened betweenthe ring 209 and a ring 211 also centred on axis X-X′.

This embodiment differs from the preceding ones in that an electricmotor 275 is integrated in the support 204 of the shaft 203 and of theafore-mentioned elements. 276 denotes the output shaft of the motor 275,this shaft being fast in rotation with a disc 277 for driving the shaft203 in rotation.

The outer casing 278 of the motor 275 has substantially the samegeometry as the support 4 of the first embodiment.

The catch 206 is articulated about a pin 207 fixed on a part 205 in onepiece with the support 204.

This embodiment presents the particular advantage that all the functionsof motorization, of compensation and of safety of the mechanism 201 aregrouped together in a compact device which may be pre-assembled in thefactory, before it is placed in position inside an end of the shaft 203.

In the fourth form of embodiment of the invention shown in FIG. 6,elements similar to those of the first embodiment bear identicalreferences increased by 300. The mechanism 301 of this embodimentcomprises a tube 303 for the controlled winding of a screen body T aboutan axis X-X′ which is also the axis of symmetry of the tube 303.

A fixed shaft 304 extends inside the shaft 303 and a spring box 400 isinterposed between the shafts 303 and 304. This spring box comprises acompensating spring 310 of which one end 310 a is fast with an innerradial part 401 of the box 400 and of which the other end 310 b is fastwith an annular element 309 mounted, with possibility of rotation, on aring 308, itself fast with the shaft 303. As previously, a ring 320constitutes a shoe capable of braking a catch 306 supported by amechanical pin 307 fast with a lateral partition 305 of the spring box400, this lateral partition being, in practice, in one piece with thepart 401 which is fixed with respect to the shaft 304.

Springs 330 make it possible to exert on the annular part 309 an efforttransmitted by a rib 394 to a groove 324 of the ring 320 and tending toapply the ring 320 against the catch 306, as represented by the arrow ofeffort F₂. When the spring 310 correctly ensures its function ofcompensation, the effort exerted by the springs 330 is overcome by thespring 310, with the result that the ring 320 is maintained at adistance from the catch 306 by maintaining a clearance J, as representedby the arrow of effort F.

The geometry of the grooves 24 and of the ribs 94 or of the equivalentelements of the second, third and fourth embodiments, is not necessarilyhelicoidal.

The rings 108, 208 and 308 of the second, third and fourth embodimentsare respectively provided with toothings 189, 289 and 389 similar to thetoothing 89 of the first embodiment.

In the fifth form of embodiment of the invention shown in FIGS. 7 to 10,elements similar to those of the first embodiment bear identicalreferences increased by 500. In this mechanism 501, a winding shaft 503is provided to rotate about an axis X-X′ to allow the controlled windingof a screen body T. A ring 505 is fixed by a bracket (not shown) to themasonry of a building. A catch 506 is fast, in rotation about axis X-X′,with the shaft 503 which defines a housing 503 a for receiving the catch506. The catch 506 is provided with two branches 561 and 562 and with acentral body 563.

The branch 561 is adapted to cooperate with an inclined toothing 589formed on the periphery of the ring 505.

A spring blade 571 exerts on the branch 562 an effort F₃ intended toinduce a pivoting of the catch 562 about its axis X₁-X′₁ of articulationon the shaft 503 in the direction of arrow F₄ in FIG. 10, this havingthe effect of moving the branch 561 away from the toothing 589.

Axes X-X′ and X₁-X′₁ are substantially parallel.

The branches 561 and 562 are substantially balanced, this allowing thecatch 506 to function efficiently, as mentioned with reference to thecatches of the previous embodiments, independently of the orientation ofthe shaft 503 about axis X-X′.

A compensating ring 510 is provided in the installation and is blockedon a ring 509, itself mounted to pivot about the ring 505. The ring 509is provided with a radial extension 591 intended to penetrate in a notch503 b made in the shaft 503, a spring 530 being interposed between theextension 591 and one of the sides of the notch 503 b. This springexerts on the extension 591 an elastic effort F₅ oriented towards theleft in FIG. 8.

In the event of rupture of the spring 510, the effort F₅ has the effectof displacing the ring 509 with respect to the shaft 503 towards theleft in FIG. 8 and upwardly in FIG. 9, this having the effect ofbringing a surface 592 made on the ring 509 into abutment against an endfinger 564 of the catch 506.

The surface 592 is inclined with respect to the axis X₁-X′L and withrespect to the axis X-X′, with the result that the displacement of thering 509 under the effort F₅, which displacement is represented by arrowF₆ in FIG. 9, has the effect of pushing the finger 564 and the catch 506assembly in the direction of arrow F₇.

This has the effect of bringing the rear face 565 of the catch 506 intocontact with a friction pellet 572. The contact between the face 565 andthe pellet 572 brakes the oscillations of the catch 506 around the axisX₁-X′₁, with the result that a rapid and efficient blocking is obtainedof the catch 506 with respect to the toothing 589, i.e. animmobilization in rotation of the shaft 503.

According to a variant of the invention (not shown), the pellet 572might be mounted on the catch 506, in which case it would be displacedwith the catch in the direction of a lateral face 503 c of the shaft503.

In the sixth form of embodiment shown in FIGS. 11 to 13, elementssimilar to those of the first embodiment bear identical referencesincreased by 600. The mechanism 601 of this embodiment differs from thepreceding one in that, in the event of rupture of the compensatingspring 610, the ring 609 fast with the compensating spring 610 acts byits extension 691 directly on a finger 666 of the catch 606, and thisunder the effect of an effort F₅ exerted by a spring 630.

Under the effect of the effort exerted by a lateral face 692 of theextension 691, the catch 606 tips in the direction of arrow F₈ in FIG.12, which has the effect of bringing its branch 661 into engagement witha toothing 689 provided on a ring 605 fixed with respect to thestructure of the building and around which the ring 609 is mounted.

As previously, the catch 606 is received in a housing 603 a made in theshaft 603 for winding the screen body T.

A spring 671 exerts on the catch 606 an elastic effort F₃ for moving thebranch 661 away with respect to the toothing 689.

In the fifth and sixth forms of embodiment, the housings for receivingthe catch may be obtained by assembling a plurality of parts togetherconstituting the shaft 503 or 603.

In the seventh form of embodiment of the invention shown in FIGS. 14 to16, elements similar to those of the first embodiment bear identicalreferences increased by 700. The mechanism 701 of this embodiment alsocomprises a ring 705 fixed with respect to the structure of a buildingas well as a ring 709 mounted to pivot about the ring 705 and fast inrotation with a compensating spring 710. A shaft 703 is provided for thecontrolled winding of a screen body T by its rotation about asubstantially horizontal axis X-X′.

A plurality of oscillating catches are provided in this device in themanner described in EP-A-0 671 543, these catches, of which only one isshown in the Figures with reference 706, are of cylindrical shape, withcircular cross-section and rectilinear generatrix and are capable ofmovement of radial oscillations with respect to axis X-X′, in thedirection of the double arrow F₉ in FIG. 14.

The catches 706 are provided to cooperate with a toothing 789 providedon the ring 705. A complementary toothing 790 is associated with thetoothing 789 in order periodically to displace the catches 706 in thedirection of the toothing 789, during rotation of the shaft 703.

An extension 703 d is provided on the shaft 703 to extend inside ahousing 793 made in the ring 709 and inside which is also disposed aspring 730 exerting on the extension 703 d an effort F₅ directed towardsthe right in FIG. 15 and overcome by the torque exerted by the spring710 when the installation is functioning normally. In the event ofrupture of the spring 710, the effort F₅ displaces the extension 703 dinside the housing 793, which has the effect of displacing the ring 709in rotation with respect to the shaft 703, as represented by arrow F₆ inFIG. 16. A radial notch 794 is provided in the ring 709 while a shuttle780 is installed in the housing 703 e provided in a piece 703′ fast withthe shaft 703. The lateral faces 794 a and 794 b of the notch 794 areflared, this making it possible, during the displacement F₆, to exert onthe shuttle 780 an effort F₁₀ which is centrifugal with respect to axisX-X′ and having the effect of displacing the end 780 a of the shuttle780 radially towards the outside, this pushing the catch 706 radially inthe direction of arrow F₁₁ and preventing a fresh introduction of acatch 706 in the housing 703 f normally provided therefor in the shaft703. In this way, the catch 706 comes into engagement with the toothing789 and the mechanism is blocked in rotation.

In practice, a shuttle 780 is provided under each housing 703 f.Furthermore, the ring 709 comprises a plurality of radial notches 794corresponding to the different shuttles 780. In addition, the tooth ofthe toothing 789 visible in FIG. 16 is bordered by a part 789 a ofrelatively small radius of curvature then by a part 789 b shownpartially in dashed and dotted lines in this Figure, this partapproaching the ring 709 while moving away from part 789 a, with theresult that the catches disposed opposite the part 789 b cannot leavetheir respective housings, no radial clearance being possible when thepart 789 a is adjacent the ring 709. This is why the two ends 780 a and180 b of the shuttle 780 are connected by a blade 780 c forming spring.In effect, in the case of rotation of the ring 709 with respect to theshaft 703, all the shuttles are stressed radially by the sides of thenotches 794 and only the one which is disposed at the level of catch 706opposite the part 789 a may effectively be displaced. The other shuttlesare compressed, by bringing together their ends 780 a and 780 b againstthe effort generated by the spring 780 c.

The invention is not limited to the forms of embodiment described andthe technical characteristics thereof may, in particular, be combined.

The invention has been described with a screen body T selectivelywindable around a shaft for closing an opening O. However, it isapplicable whatever the nature of the closing means used, which may inparticular be a rigid or semi-rigid panel controlled thanks to strapsthemselves wound on a shaft.

1. A safety device for a closing installation comprising: a mechanismfor driving a screen body for selectively closing an opening, saidmechanism including: a shaft for winding and unwinding said screen body,an element having teeth, said element being mounted to said shaft, atleast one catch which successively contacts said teeth and oscillatesover said teeth of said element to permit rotational movements of saidshaft as said screen body is being unwound, and a braking means forbraking said at least one catch by preventing further oscillation ofsaid at least one catch and causing said at least one catch to engagesaid teeth of said element in a non-oscillating manner to thereby causesaid shaft to be immobilized, said braking means being controlled by adetection means for detecting a failure of a compensating means forcompensating for a torque exerted on said shaft by said screen body, andsaid braking means having a shoe axially moveable along an axis (X-X′)with respect to said shaft and adapted to come into abutment againstsaid at least one catch.
 2. The safety device according to claim 1,wherein said shoe has at least one first member, said at least one firstmember is adapted to cooperate with at least one corresponding secondmember of an annular ring that rotates with said compensating means forcontrolling the axial position of said shoe with respect to said atleast one catch.
 3. The safety device according to claim 2, wherein saidat least one first member is a groove and said at least one secondmember is a rib that is engageable within said groove.
 4. The safetydevice according to claim 2, wherein the at least one first member isformed on a tongue extending through an opening in said element thatrotates with said shaft.
 5. The safety device according to claim 2,wherein said shoe and said annular ring are disposed axially on eitherside of said element and kinematically connectable by said at least onefirst member and at least one second member.
 6. The safety deviceaccording to claim 1, wherein said mechanism further includes means forapplying an elastic force of displacement of said shoe toward said atleast one catch.
 7. The safety device according to claim 2, wherein saidannular ring and said element have ribs between which at least onecompression spring is disposed, said at least one compression springexerts a rotational torque of said annular ring with respect to saidelement.
 8. The safety device according to claim 1, wherein saidmechanism includes a motor, and wherein said shoe is a ring disposedinside said shaft and around a support for said motor, said motor havingan output that is drivingly connected to said shaft.
 9. The safetydevice according to claim 1, wherein said braking means is adapted todisplace said at least one catch toward a braked position.
 10. Thesafety device according to claim 9, wherein said mechanism furtherincludes a friction pellet mounted on said catch and adapted to receivesaid at least one catch in abutment.
 11. The safety device according toclaim 10, wherein said braking means has a surface formed on a ring thatrotates with said compensating means and adapted to exert, directly orindirectly, a force of displacement on said at least one catch.
 12. Thesafety device according to claim 11, wherein said surface extends in adirection substantially inclined with respect to an axis of rotation(X-X′) of said shaft, said surface forming a ramp adapted to displacesaid at least one catch toward a braked position.
 13. The safety deviceaccording to claim 11, wherein said surface is substantially radial withrespect to an axis of rotation (X-X′) of said shaft, said surface beingadapted to cooperate with a finger of said at least one catch in orderto tip said at least one catch about an axis of oscillation toward abraked position by engagement with said teeth.
 14. The safety deviceaccording to claim 13, wherein said mechanism further includes means forreturning said at least one catch from said braked position.
 15. Thesafety device according to claim 9, wherein said braking means has atleast one shuttle adapted to displace said at least one catch in adirection of fixed blocking teeth.
 16. The safety device according toclaim 15, wherein said shuttle has an elastic means for adjusting thelength of the shuttle between a bearing surface and said at least onecatch.
 17. The safety device according to claim 9, wherein saidmechanism further includes means for elastic return of said brakingmeans toward a position in which said means exerts on said at least onecatch a force of displacement toward said braked position.
 18. Thesafety device according to claim 1, wherein said at least one catch ismounted on a fixed element of said installation.
 19. The safety deviceaccording to claim 1, wherein said at least one catch is mounted on andadapted to be driven in rotation by an element that rotates with saidshaft.
 20. The safety device according to claim 1, wherein said brakingmeans, said detection means, and said compensating means is arrangedaround a support for a motor of said mechanism.
 21. The safety deviceaccording to claim 1, wherein said compensating means is a spring woundaround an end support of said shaft, between a part fixed with respectto said support and an annular member adapted to rotate about saidsupport as said support is driven by said shaft, said at least one catchbeing mounted to pivot about a pin fixed with respect to said support.22. The safety device according to claim 1, wherein said compensatingmeans is a spring that is compressed by a weight (P) and that rotateswith an annular member surrounding an end support of said shaft, said atleast one catch being mounted to pivot about a pin fixed with respect tosaid support.
 23. The safety device according to claim 1, wherein saidcompensating means is a spring wound around a motor assembly disposedinside said shaft, said at least one catch being mounted to pivot abouta pin fixed with respect to an end support of said shaft.
 24. The safetydevice according to claim 1, wherein said compensating means is a springwithin a spring box disposed inside said shaft, between said shaft and afixed shaft, said spring box also contains said at least one catch, saidbraking means, and said detection means.
 25. The safety device accordingto claim 1 wherein said shoe is a ring disposed inside said shaft andaround a support and a motor assembly for said mechanism.
 26. The safetydevice according to claim 9, wherein said mechanism further includes afriction pellet, mounted opposite said at least one catch, and adaptedto come into contact with a bearing surface of said at least one catch.27. The safety device according to claim 9, wherein said mechanismfurther includes means for elastic return of said braking means toward aposition in which said means exerts on said at least one catch a forceurging said at least one catch toward said braked position.
 28. Thesafety device according to claim 1, wherein said braking means, saiddetection means, and said compensating means are arranged around asupport and motor assembly for said mechanism.
 29. A mechanism formoving a closing installation comprising: a shaft for winding andunwinding a screen body; an element having teeth, said element beingmounted to said shaft; at least one catch which successively contactssaid teeth and oscillates over said teeth of said element to permitrotational movements of said shaft as said screen body is being unwound;and a braking means for braking said at least one catch by preventingfurther oscillation of said at least one catch and causing said at leastone catch to engage said teeth of said element in a non-oscillatingmanner to thereby cause said shaft to be immobilized, said braking meansbeing controlled by a detection means for detecting a failure of acompensating means for compensating for a torque exerted on said shaftby said screen body, and said braking means having a shoe axiallymoveable along an axis (X-X′) with respect to said shaft and adapted tocome into abutment against said at least one catch.
 30. A safety devicefor a closing installation comprising: a mechanism for driving a screenbody for selectively closing an opening, said mechanism including: ashaft for winding and unwinding said screen body, said shaft beingcapable of rotating in a first direction as the screen body is wound andcapable of rotating in a second direction as the screen body in unwound,an element having teeth, said element being mounted to said shaft, atleast one catch which successively contacts said teeth and oscillatesover said teeth of said element as said shaft rotates in the seconddirection, and a braking means for braking said at least one catch bypreventing further oscillation of said at least one catch and causingsaid at least one catch to engage said teeth of said element in anon-oscillating manner to thereby cause said shaft to be immobilized,said braking means being controlled by a detection means for detecting afailure of a compensating means for compensating for a torque exerted onsaid shaft by said screen body, and said braking means having a shoeaxially moveable along an axis (X-X′) with respect to said shaft andadapted to come into abutment against said at least one catch.
 31. Aclosing installation comprising a screen body for selectively closing anopening and a safety device, said safety device including: a shaft, saidshaft being capable of rotating in a first direction as the screen bodyis wound and capable of rotating in a second direction as the screenbody is unwound, an element having teeth, said element being mounted tosaid shaft, at least one catch which successively contacts said teethand oscillates over said teeth of said element as said shaft rotates inthe second direction, and a braking means for braking said at least onecatch by preventing further oscillation of said at least one catch andcausing said at least one catch to engage said teeth of said element ina non-oscillating manner to thereby cause said shaft to be immobilized,said braking means being controlled by a detection means for detecting afailure of a compensating means for compensating for a torque exerted onsaid shaft by said screen body, and said braking means having a shoeaxially moveable along an axis (X-X′) with respect to said shaft andadapted to come into abutment against said at least one catch.
 32. Asafety device for a closing installation comprising: a mechanism fordriving a screen body for selectively closing an opening, said mechanismincluding: a shaft for winding and unwinding said screen body, anelement having teeth, said element being mounted to said shaft, at leastone catch which successively contacts said teeth and oscillates oversaid teeth of said element to permit rotational movements of said shaftas said screen body is being unwound, said at least one catch beingmounted on a fixed element of said installation, and a braking means forbraking said at least one catch by preventing further oscillation ofsaid at least one catch and causing said at least one catch to engagesaid teeth of said element in a non-oscillating manner to thereby causesaid shaft to be immobilized, said braking means being controlled by adetection means for detecting a failure of a compensating means forcompensating for a torque exerted on said shaft by said screen body.